Cut-off valve



UNITED STATESPATENTOEEICE.; f

HENRY H. GRAME,v 0E PATEiisoN, NEW JERSEY.`

CUT-OFF VALVE.l

Specification of Letters Patent N o. 5,026, dated March 20, 1847.

To all whom t may concern.'

Be it kno-wn that I, .HENRY I-I. GRAME, of

allowing the steam to work through theV whole stroke of the piston. And I do hereby declare that the following is a full clear and exact description of the construction and operation of the same, reference being had to the annexed drawings making part of this specification, in which- Figure I is a perspective View, and Figs. II, III, and IV, are plans.

Similar letters refer to similar' parts in all the figures.

To the ordinary slide valve of the steam engine, I attach four pieces of metal a, a, a a called hooks. These hooks are so contrived as to operate on four other pieces of metal Z9, ZJ, b, b, called rockers. These rockers are hinged at one end, near the end plates of the steam chest. Each rocker has a pin driven in near its center, which pin passes up through the opening in the hooks.

There is also attached to the main valve, four springs c 0 c c, which press against thebacks of the hooks a', tending to force them inward toward each other.

The letters el, d, represent an independent cut off valve. These'are two pieces of metal, having four sides forming a square, and lie parallel to the edge of the main valve, on either side. Their length and face must be of such dimensions as to cover the steam openings (when o-n them). The letters e, e, represent two shafts passing through the top of the steam chest. They have attached, at their lower ends a cross piece or stop g g,

and on their tops,two arms it, 7L', and a connecting rod .12 These operate on the hook, and is'the contrivance for connecting or disconnecting the cut off valves.

The operation is as follows: On starting the engine the main valve m has its ordinary reciprocating motion. It is seen advancing toward and the Steam is passing into the cylinder through the opening in the direction of the arrow. As the valve carries thel hooks alo-ng with it, they in turn operate on the rockers b b. The pins in the 'rockers beingmidway, from end to end, give to the outer end, an accelerated motion, and the twoouter ends acting against the cut off valve'd, causes it to advance toward the main valve m, with twice its velocity, so that when the piston has arrived at half stroke or any given part thereof according to the set of the valve), the cut off valve Z has overtaken ythe main valve m, and consequently closed the steam opening soas to prevent the ingress of any more steam'to the cylinder during the rest of the stroke. The hooks a', a, a, a, only operate to cause the cut oft' piece cl to follow after the main valve, and close the steam'openings, the main valve on its return, pushing it back to the place of starting, as seen at CZ Fig. I. A

The cut off can be disconnected, at any time, either during the working `of the engine or when at rest by means of the parts it, L, z', which connect with the -stops g, g. When in gear the stops g g stand parallel to the hooks a, a, a', a, as seen in Figs. I and III. In disconnecting the armV L' is moved toward the pin nearz' on the top of the steam chest. This causes the ends of the stops g, g, to press apart the hooks, (as seen at Fig. II), which prevents them from operating on the rockers b. b. b. 7). The springs c c c c force the hooks into gear on removal of the stops g, g. Y

vThe principal advantage in this arrangement is the manner of connecting the cut o valves with the ordinary slide valve,v

and operating the whole by one stem or rod, and a single external connection, with theV ability to unhook, and put on the whole force of they steam at any moment, whether in mo- 10 main valve m,-the hooks a, a, a, a', rockers Z), b, b, b', andthe stops g, g. The said several parts being contained Within the steam chest, and Worked by the main Valve m, 0perating and combined irl the manner and for the purposes herein set forth.

HENRY H. GRAME.

lVtnesses:

JOSEPH P. PIRSSON, Jr., J. L. KINGSLEY. 

